Relay



Aug. 18, 1931. L. CRICHTON ETAL: ,501

RELAY Filed Aug. 23, 1926 3 Sheets-Sheetv 1 WITNESSES:

l INVENIORS Les/12M Cr/chfan 4Q J ZTT'ORNEY 8- 1931- L. N.'YCRICHTONI ETAL 1 ,819,501

RELAY 3 Sheets-Sheet 3 Filed Aug. 23, 1926 yTNlTyN/ESSES: i Him A RNEY Patented Aug. 18, 1931 UNITE STATES LESLIE -N. GRICHTON AND JOHN V. BRCEISK Y, OF PITTSBURGH, PENNSYLVANIAK" ASSIGNORS T WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A COR,-

PORATION OF PENNSYLVANIA RELAY Application filed August 2-3, 1926. Serial No. 130,784.

Our inventionrelates to electrical relays andparticularly to overload relays for alternating or direct-current circuits. An object of our invention is to provide an 5 accuratetime-element relay having characteristics similar to those of the inductiontype alternating-current relay, but having a simpler field-magnet structure and being adapted for either alternatingor directofcurrent circuits.

Another object of our invention is to provide a time-element relay of the above-mentionedcharacter that shall be instantaneous inrespect to the closure of the movable contact member when energized, and retarded in :respect to the resetting thereof or vice'versa.

' i A further object of our invention is to pro- ;vide anelectromagnetic relay having a field magnet provided with salient pole pieces and an improved magnetizable shunt member for ,adjusting the strength of the magnetic flux in said pole pieces.

d Other objects and advantages of our invention will appear from the following detailed description of a relay constructed in accord- I ance therewith. In the accompanying drawings,

Fig. 1 is aplan view of a relay embodying the invention with the movable contact member in the open or de-energized position. Fig. 2'is a front view of the relay shown I in Fig. 1,-with the movable contact member in the closed or actuated position. 7 Fig.3 is a side view, partially in section, of the relay shown in Figs. 1 and 2;

Fig. 4 is a simplified diagram of the ar- .Figs. 5 to 8, inclusive,,are detailed views to an enlarged scale of the magnetic shunt and the pawleand-ratchet mechanism of the I relay shown in Figs l to 3.

Referring to Figs. 1 to 3, the relay shown vertical spindle or shaft 2 is pivoted in bearings 3 and 4. An armature member 5 and a discImember 6 are mounted upon the shaft 2. :A field-magnet structure 7 cooperates with the armature member 5. A permanent comprisesa frame member 1 upon which av magnet 8 cooperates with the disc member 6 to damp the 'movements thereof. The damping magnet 8 may be replaced by an PATENT OFFICE electromagnet or may be omitted if it is desired that therelay shall have instantaneous operating and resetting time characteristics.

The armature member 5 comprises a magnetizable segment 10 of iron disposed eccentrically with respect to the shaft 2 in an aper- :2

ture in a substantially circular'disc, member 11 of brass or similar non-magnetizable metallsee Figs. 1 and 3). The thickness and configuration of the magnetizable. armature member dependsiupon the desired operating. characteristics of the relay. The thickness of the disc memberv 11 is preferably such that the weight per unit area, is the'same as that of armature member 10. Since the. armature member 1s mounted in an aperture 111::

the disc member 11 and the two members are of equal weight per unit area, the composite armature member comprising the magnetizable and non-magnetizable portions 10 and '11 is balanced upon the shaft 2. Accord-: ingly the bearings 3 and 4 maybe delicate and substantially frictionless and no error is introduced by an unbalance ofthe moving element of the relay.

As shownin' Fig. 3, the upper bearing 3;

may be of the pin type because the lateral thrust against the bearing is slighton ,account of the fact that the entire moving element is substantially balanced. The bearing shaft 2 engaging a stationary bearing mema ber 13 on the frame 1. The lower bearing 4 'rangement of the field magnet and armature member of the relay shown in Figs. .1 to 3,.

comprises a steel ball 15 disposed between sapphire or other jewel bearings 16and 17 on the shaft and frame, respectively. The 5pro-:

, 3comprises a pin 12 in the upper end of thetance and is essential to the success of the inof field magnet and armature shown, including the mounting of the armature and damping disc members on a single shaft.

The field-magnet structure 7 comprises a magnetizable member 20 to which an upper soft-iron piece 21 and two parallel magnetizable members 22 are secured. findings 23 are disposed on the field elements 22. A soft-iron pole piece 211 is secured to the upper ends of the members 22 opposite the upper pole piece 21. The movable armature member 5 is disposed in the air-gap between the salient pole pieces 21 and 2st, as shown in Fig. 3. For alternating-current circuits, the field magnet may be laminated, if desired.

Referring particularly to Fig. l, the windings 23 are cumulative in effect, as shown, so that they might be replaced by a single winding. However, the splitting of the lower pole piece into two parallel portions increases the winding space available and permits the disposition of the windings on either side of the disc member 6, thereby rendering the structure of the relay more compact, as clearly indicated in Figs. 1 and 3.

A movable contact member 30 is secured to the spindle 2 and is adapted to cooperate with the stationary contact members 31 and 32 de pending upon the energization of the winding 23. The fixed contact members 31 are supported upon a pivoted adjusting arm 33 which may be turned about the axis of the shaft 2. The adjustment of the arm 33 alters the spacing of the contact members 30 and 32 and thereby changes the operating time of the relay, since the movement of the armature member is damped by the damping magnet 3. A scale 34 may be provided for cooperation with the movable arm 33 to facilitate the timing adjustment of the relay and to indicate the time setting after the relay has been adjusted.

A restraining spring 35 is secured to the frame member 1 and the shaft 2 and normally holds the contact member 30 in engagement with the stationary back contact members 31. \Vith the contact members in this position, the magnetizable armature member 10 is in the position shown in Fig. 1. lVhen the current traversing the winding 23 increased until the torque of the armature member 10 is sufiicient to overcome the restraining torque of the spring 35, the armature member is attracted to a position between the upper and lower pole pieces 21 and 2%, thereby actuating the movable contact member 30 to the position shown in Fig. 2 in engagement with the stationary front contact members 32.

. The movement of the contact member 30 from the retracted position to th operated position is damped by means of the damping magnet 3 which cooperates with the disc member 6. The disc member 6 is loosely mounted on the spindle 2 but is provided with two pawl members 39 cooperating with a ratchet member 40 secured to the shaft (see Figs. 3, 7 and 8). The pawl members 39 are normally held in engagement with the ratchet 40 by the spring members 41. When the relay operates and then becomes tie-energized, the pawl members 39 are ineffective insofar as the connection between the shaft 2 and the disc member 6 is concerned and the shaft and movable cont-act member 30 reset practically instantaneously to the initial position under the retractive effort of the restraining spring 35, the movement being independent of that of, the damping disc 6. If it is desired that the relay shall operate instantaneously and reset slowly, it is only necessary to reverse the pawl members 39 so that they will cooperate with the ratchet 40 in the reverse direction of movement.

A magnetizable shunt member 45, which is adapted to control the flux in the salient pole pieces 21 and 2 1, is mounted on the lower pole piece 24. The shunt member A5 is provided with a projection portion 46 (see Fig. 1) and is adapted to be so ad usted as to move a variable area of said pro ecting portion 1nto close proximity with the field member 20 (see Figs.

1 and 3). A retracting spring 47 is secured to one end of the shunt member 45.. A flexible wire 18 running over pulleys ll) and 50 is secured to the other end of the shunt member.

The lower end of the flexible wire 48 is se cured to a screw-threaded adjusting means 51. The w1re 43 may be prov1ded with an idicator 52 thereon cooperating wlth a scale 53 as shown in Fig. 2 to facilitate the adjustment of the relay.

The adjustment of the shunt member 45 alters the amount of flux traversing the air gap between the pole pieces 21 and 2a for a predetermined current in the winding 23. Consequently the adjustment of the shunt member determines the operating current required in the relay windings independently of the torque of the restraining spring 35 which may also be made adjustable.

The amount of flux which is shunted from the pole pieces by the member 45 depends upon the extent to which the projection 46 overlaps the field member 20. The portion of the projection 46 which is in close proximity to the field member 20 becomes saturated before a substantial amount of flux may traverse pole tips. Consequently the relation between the operating current in the field windings and the position of the shunt member is a linear one, as indicated by the equal scale division upon the scale 53.

A contactor switch 55 is connected in shunt relation to the contact members of the relay in order to decrease the currentinterrupting duty imposed upon the relay contact members. The relay may also be provided with a card holder 56 for holding a card bearing inscriptions of curves showing the characteristics of the relay. The front of the relay is enclosed dow is provided in front of the card holder 56.

The relaywhich is shown and described herein has been found to have accurate and satisfactorytime-element characteristics and is adapted for either direct-current circuits or relatively low-frequency alternating-current circuits, such as the ordinary commercial frequencles. The relay 1s simpler than the mductlon-type relay for alternatmg-current applications and provides a direct-current time-element relay for applications for -whichno satisfactory direct-current relay has heretofore been available.

Various modifications of the structure which We have shown and described in detail will occur'to those skilled in the art, and, accordingly, we

do notwish to be limited to thespecific modification which we have shown and described except as may be indicated in the appended claims.

,VVe claim as our invention:

1. An electromagnetic relay comprising a movable .magnetizable armature member, a field magnet having a split pole piece cooperating with said armature member, windings on therespective portions of said split pole piece, means including said field magnet and windings for controlling said armature member when said windings are energized above a predetermined degree and magnetic meansfor damping the movement of said armature.

2. An'electromagnetic relay comprising a fiat magn etizable balanced armature member pivoted to move in its own plane, a cooperating field magnet having salient pole pieces.

on opposite sides of the armature member along the axis thereof, a winding on said field magnet and means including said winding for actuating said armature member when the current traversing the winding exceeds a predetermined value.

An electromagnetic relay comprising a fiat horlzontal armature member of mag-v netizable metal, a vertical shaft for said armature member, means for balancing said armature member with respect to said shaft, an electromagnet cooperating with said armature member and means including said electromagnet for actuating said armature member when the current traversing the electromagnet exceeds a predetermined value.

4. An electromagnetic relay comprising a movable armature member, contact members controlled thereby. a field magnet having salient pole pieces adjacent said armature member, an adjustable magnetic shunt mounted on said field magnet to control the flux traversing the armature member, a retractmg spring connected to said magnetic disc of non-magnetic material, a permanent magnet associated therewith, and cooperating means on said spindle and disc for effecting a driving connection therebetween only upon movement of, said armature in a predetermined d-irection.

7. The combination with the operating mechanism of an electrical instrument in cluding a rotatable spindle, of means for damping the movement of said, spindle in one directiononly including a damping disc loosely mounted on said spindle and means on said disc and spindle for effecting a driving connection therebetweennpon rotation of said spindle in a predetermined direction.

8. The combination with the operating mechanism of an electrical instrument including a rotatable spindle, of means for LESLIE N. CRICHTON. JOHN v. BREISKY. 

